How to Work a Coffee Pot and What Determines Black, Yellow and Dark Tea Flavor?

Turning fresh leaves into dry tea takes picking, withering, leaf shaking, oxidation, fixation, yellowing, drying, and aging. The oxidation level and the way it is stopped decide which category the finished tea lands in and shape its aroma, flavor, and appearance. Black, yellow, and dark teas follow broadly similar steps, differing mainly in detail and in how temperature and humidity are controlled.

Picking usually happens twice a year, taking one bud and two leaves, mostly in early or late spring. If humidity and temperature are not managed during processing, mold can grow and cause true fermentation, spoiling the batch. The same flavor logic runs through coffee: roast and processing method steer what ends up in the cup, much as they do when learning how to work a coffee pot at home.

Turning fresh leaves into brewable dry tea requires a series of refined processing steps. Different processing paths—especially the degree of oxidation and the method used to halt it—directly determine which category the finished tea belongs to, and also shape its aroma, flavor, and appearance. This article systematically reviews the stages of tea picking, withering, leaf shaking, fermentation/oxidation, fixation, yellowing, drying, and aging, and compares the key differences in the production of black tea, yellow tea, and dark tea. It also analyzes how temperature and humidity control affect quality, and how tea-making steps act on the final taste. The article also combines recommendations from the Front Street brand to help coffee lovers understand the similarities between tea and coffee in flavor processing.

The process of turning fresh tea leaves into dry tea is collectively called tea processing. The dry tea is ultimately used for brewing and drinking, and the processing method largely determines which category the tea belongs to.

Classification of Tea

Tea is mainly divided into four major categories: green tea, white tea, black tea, and oolong tea. They all use the leaves and tender buds of the tea plant as raw materials. Sometimes, to adjust the flavor of the finished product, different tea types are blended, or other flavors are added, to create unique blended teas and tastes.

The differences in processing techniques are reflected in the oxidation method, the degree of oxidation, the means of stopping oxidation, and the finished tea and drying methods. The flavor of the final dry tea is influenced both by the tea plant variety and the quality of the fresh leaves, and also closely related to the execution level of production and processing.

Different tea types each have unique mouthfeel, flavor, aroma, and appearance. The processing of all types of tea consists of fairly similar methods and steps, with only slight adjustments in the details. It should be noted that if humidity and temperature are not properly controlled during processing, mold can easily grow on the tea leaves. This mold can cause true fermentation, contaminating the tea and making the finished product no longer suitable for drinking.

Tea picking—usually carried out twice a year, picking one bud and two leaves from the tea plant. Picking mostly occurs in early spring or late spring, and this same-flush approach is more common. Another less common picking method is carried out in autumn or winter, often appearing in production areas where the climate allows picking. The buds and leaves of high-quality tea are mostly picked by hand, even in places where labor costs are not high. The skill of the picker is crucial and directly affects the final finished product. During hand picking, the flush is pulled by breaking the forearm, arm, or even shoulder. The picker pinches the tea bud with the thumb and index finger, sometimes also using the middle finger. If not by hand, it is harvested by machine. But machines easily cause leaf breakage and some bruising, reducing tea quality. However, if harvested by machine at the correct harvest time, high-quality leaves can also be obtained for producing high-quality tea.

Withering—fresh leaves begin to wither soon after picking. In other words, enzymatic oxidation has already started shortly after picking. To avoid excessive oxidation, withering techniques are used to remove excess moisture from the leaves, allowing only a very small amount of oxidation to occur. During dehydration, the leaves are either spread out in the sun or placed in a cool rolling room. At this stage, due to moisture loss, the leaf weight often decreases by more than a quarter. This withering process is also essential because it promotes the breakdown of proteins in the leaves into free amino acids.

Leaf shaking—also called leaf bruising. In this step, the tea leaves are crushed or torn to promote and accelerate oxidation. This is done by slightly bruising the edges of the leaves, achieved by shaking and tossing the tea on bamboo trays, or tumbling it in baskets. If more extensive leaf damage is needed, kneading, rolling, tearing, and crushing can be used, usually done by machine. This step helps break down the internal and external structures of the leaf cells, thereby initiating oxidation, while also releasing leaf juices and changing the tea's flavor.

Fermentation/oxidation—for tea types that require oxidation, the leaves are left to oxidize in a climate-controlled room, gradually darkening in color. This may be accompanied by varying degrees of agitation, leading to different results. In this step, the chlorophyll in the leaves breaks down, and tannins are released. This oxidation process is sometimes also called fermentation.

Fixation—this step is to control leaf oxidation at the desired level to produce various types of tea. It is done by moderately heating the tea leaves to deactivate the oxidizing enzymes. This process also helps remove unwanted aromas from the tea without damaging the final flavor.

Yellowing—also called turning yellow, unique to yellow tea. After the previous stage is completed, the warm and moist tea leaves are placed in a sealed container and gently heated, causing the green leaves to turn yellow. As the chlorophyll in the leaves changes, the tea produced by this technique forms a yellow-green tea liquor. Rolling the moist tea leaves into wrinkled strips can be done by hand or by machine. This process further strengthens the flavor, because it causes some of the juices as well as the essential oils and juices in the tea leaves to seep out.

Drying—this is the final step before the tea is ready for sale. There are various drying methods, including pan-firing, sunlight, air drying, or roasting. Among these, roasting is the most commonly used. For green tea, this step is especially important.

Aging—not all tea types require this step. This is an additional aging process, forming the leaves only through secondary roasting, to reach their drinking potential.

The above content is compiled by CoffeeHunters, a coffee news website.